Mauna Loa

Mauna Loa - Page Text Content

S: Mauna Loa

BC: Mauna Loa is a giant, active basaltic shield volcano which rises over 4 km above sea level, another 5 km above the north-central Pacific seafloor, and another 8 km above the isostatically depressed seafloor of the Pacific Plate, for a total volcanic height of 17 km. It is the most voluminous volcano on Earth (>75,000 km ), with a subareal surface area of over 5,000 km (half the Island of Hawaii). Mauna Loa is one of the Earth's most active volcanoes, having erupted more than 30 times since its first documented historical eruption in 1843. Mauna Loa has been selected as one of 15 "Decade Volcanoes" by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI). This status provides opportunities for increased multidisciplinary and multinational efforts to understand volcanic processes and better monitor this great volcano, with the purpose of mitigating volcanic hazards at this and at similar volcanoes around the world. | A brief introduction about Mauna Loa...

8: Effects on the Enviroment | Volcanic gases that pose the greatest potential hazards are sulfur dioxide, carbon dioxide, and hydrogen fluoride. Locally, sulfur dioxide gas can lead to acid rain and air pollution downwind from a volcano. These gases can come from lava flows as well as a volcano that erupts violently.Volcanic ash can travel hundreds to thousands of miles downwind from a volcano. Fresh volcanic ash is gritty, abrasive, sometimes corrosive, and always unpleasant. Although ash is not highly toxic, it can trouble infants, the elderly, and those with respiratory ailments. Ash can also get in your eyes and scratch them, especially when it's windy. Ash can be hazardous to grazing livestock and can damage or force the shutdown of drinking water and wastewater treatment facilities by clogging or damaging equipment.

9: Plan for a Volcano | HAVE A DISASTER PLAN Know whether or not you are at risk for danger. Be prepared for mudslides, flash floods, earthquakes, ash falling, acid rain and tsunamis. Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing, dust mask, goggles and sturdy shoes. Know evacuation routes. DURING A VOLCANO: Follow the evacuation order issued by authorities. Avoid areas downwind and river valleys downstream of the volcano. If your caught indoors, close all windows and doors, put machinery inside a barn, and bring animals inside. If you’re trapped outdoors, seek shelter indoors. If you’re caught in falling rocks, roll into a ball and protect your head. If you’re caught near a stream, be aware of mudflows. Move to higher ground. Protect yourself when ash falls. Wear long-sleeved shirts and long pants. Use goggles to protect your eyes. Wear a dust mask and keep car engines off. AFTER A VOLCANO: Cover you mouth and nose. Volcanic ash can irritate your respiratory system. Wear goggles and protect your eyes. Keep your skin covered. Clear roofs of ash. The ash is very heavy and can cause the building to collapse.

10: Glossary | A Aleutian Arc - The Northern part of the Pacific Ring of Fire. The Aleutian Arc extends 1,500 miles westward to Kamchatka and forms part of the Pacific Ring of Fire. Almost all of Alaska's volcanoes are located along this arc | Ash - Measurement of particle size applied to the finest pyroclastic material, fragments less than 0.08 inches (2mm) in diameter, blasted into the air by volcanic explosions. | Basalt - Volcanic rock poor in silica but rich in magnesium, iron, and calcium. The most common volcanic rock. | B

11: C Cinders - Smaller pieces of debris too small to be called a bomb | Cinder Cone - Small mountains with steep sides that blow cinders and rock particles into the air when they erupt. Paricutin in Mexico is an example of a cinder cone | Base Surge - Turbulent low-density cloud of gas with suspended solid debris that expands radially outward from the base of an eruption column. Comparable to the ring that forms at the base of the cloud formed by a nuclear explosion. | Bomb - Fragment of magma varying in diameter from a few inches to several feet ejected into the air during a volcanic explosion (see tephra on page 21) | Caldera - Large depression produced following an eruption by the collapse of the roof of a magma chamber. Usually circular or horseshoe shaped when viewed from above.

12: Composite Cones - Large cone-shaped mountains with steep sides. Eruptions from composite cones are violent, sending up volcanic bombs, cinders, and ash. A quiet volcanic flow usually flows the explosion and helps to build up the mountain. Mount St. Helen's Washington and Mount Vernon in Italy are examples of composite cone volcanoes | Crater - A steep - sided hole at the top of the volcano that sometimes contains a pool of lava | Compound volcano - Volcanic structure composed of two or more vents or lava domes or stratovolcanoes, often formed at different times. | Conduit (volcanic) - Passageway, more or less cylindrical in shape through which magma rises from the magma chamber to the surface during volcanic activity. | D | Dike - Tabular body of intrusive magma that cuts across layers of a volcanic structure.

13: E | Eruption column - Vertical cloud of gas and pyroclastic fragments that forms during explosive eruptions and can reach stratospheric heights. | F | Fall deposit - Layer of fragmentary volcanic material created by fall from an eruption column or during an explosive eruption. | Fissure volcano - Structure composed of the accumulation of volcanic material on the sides of an eruptive fissure, usually associated with a ridge or rift situation. | Fumarole chimney - Vertical structure with a vent through which volcanic gases are discharged.

14: G | Geyser - Intermittent vertical jet of water produced by the heating of underground water by geothermal activity. | H | Hornito - Small cone or mound produced by the accumulation of spatter ejected by a vent. (see spatter cone on page 20) | Hot spot - Area on the planet where material from the mantle rises through a plume to reach a moving plate. | Hummocks - Small hills that rise above deposits from a volcanic avalanche. | Hyaloclastite - Fragmentary material of glassy composition produced by the rapid cooling of magma in contact with water.

15: I | Ignimbrite - Particular type of pyroclastic flow deposit containing glassy lenticular structures called flames. Ignimbrites can cover thousands of square miles of area. | L | Lahar - Indonesian word for a volcanic mud flow usually formed when an eruption melts part of a glacier on a volcano. These flows involve large quantities of volcanic material and can move at high speeds. | Lapilli - Latin word meaning "small stone". Small fragments of lava (between 0.08 inches (2mm) and 2.5 inches (6.4 cm) across) shot into the air during eruptions when still molten. | Lava - Magma that has reached the surface of the earth. It cools as it is exposed to the atmosphere

16: M | Magma - The hot, liquid rock that is found in the center of the earth. | Lava Dome - Accumulation of lava in the shape of a steep-sided dome over an eruptive vent. | Lava lake - Lake of molten lava inside a crater tens or hundreds of feet in diameter. Such lakes can remain active for many years. | Lava Plateau - A wide, flat surface formed when lava is expelled from long narrow openings in the crust and spreads rapidly. Layers are formed by multiple eruptive events. | Lithic (volcanic) - Fragments of previously formed rocks (volcanic and non-volcanic) expelled from volcanic vent during explosive activity and encased in pyroclastic deposits. | Maar - Tuff ring that has filled with water. Maars are shallow craters usually with flat bottoms filled with water.

17: P | Pacific Ring of Fire - The ring of volcanoes that circle the Pacific Ocean from the tip of South America, along the west coast of the U.S., through Alaska and the Kamchatka Peninsula, down through Japan, Indonesia, and the islands in the South Pacific | Magma chamber - Reservoir in which magma is accumulated and stored. Located within the structure of a volcano a few miles from the surface. | Pumice - Frothy volcanic rock heavily vesicled formed by the expansion of gas in erupting lava. | Pyroclast - Literally a "fire rock fragment" simply a piece of material formed by a volcanic explosion or ejected from a volcanic vent. | Pyroclastic flow - Mixture of fragmented volcanic materials and gas traveling at high speeds down the slope of a volcano. It is formed during an eruption or following the collapse of a lava dome.

18: S | Scoria - Dark, vesicled volcanic rock produced by moderately explosive activity or lava flows and resulting from blobs of gas-charged lava that have cooled in flight. | Shield Volcano - A shield volcano covers a large area, is domed - shaped, and has gently sloping sides. The lava is dark, thin, and runny so it flows quietly from a vent. Mauna Loa in Hawaii is an example of a shield volcano. Mauna Loa is also the largest volcano on earth. It makes up about 1/2 of the area of the island of Hawaii | Somma volcano - Type of volcanic structure composed of two volcanic cones, one of which (the more recent) has formed inside the other. | Spatter - Small fragments of lava ejected from a vent. Spatter is still molten when it falls to the ground thus forming cones or hornitos.

19: Spatter cone - Small, steep-sided mound or cone built up over a vent. | Stratovolcano - Volcano composed of alternating strata, or layers, of material created from lava and pyroclastic flows. | T | Table Mountain Volcano - Volcanic massif with steep sides and horizontal summit created following an eruption of lava under a glacial covering | Tephra - Generic term used for all pyroclastic materials of all sizes when ejected from a volcano. (Greek word for ashes) | Tuff - Deposited pyroclastic rock that has consolidated. | Tuff cone - Cone with relatively steep sides built up from the accumulation of fine-grained volcanic fragments produced from explosive activity resulting from the interaction of magma and water.

20: V | Vent - The opening in the earth that allows the magma to flow out on earth's surface | Volcanologists - Scientists who study volcanoes. They monitor volcanoes to try to warn people when eruptions are about to occur and to learn more about how the earth works | Volcano - A mountain that has reached the surface of the earth. It cools as it is exposed to the atmosphere | Tuff ring - Volcanic ring whose height is less than its diameter, built of debris around a volcanic vent located near water and produced by explosive activity resulting from the interaction of magma and water. | VOG - A blended word derived from the words volcanic and smog. VOG is formed by sulfur dioxide (and other gases) that mix with oxygen and moisture in direct sunlight during volcanic activity.

21: Volcanic Ash - Somewhat larger volcanic debris, up to 5 millimeters in diameter which is hot into the atmosphere | Volcanic Bombs - Debris from an eruption that is larger than 5 millimeters | Volcanic Dust - Very fine fragments of debris, up to .25 millimeters in diameters, which is shot into the atmosphere during an eruption